fsm.ts

enum States {
    Empty = 'empty',
    Liked = 'liked',
    Disliked = 'disliked'
}

enum Actions {
    Like = 'LIKE_ACTION',
    Dislike = 'DISLIKE_ACTION'
}

const state = {
    currentState: States.Disliked,
    states: {
        [States.Empty]: {
            on: {
                [Actions.Like]: States.Liked,
                [Actions.Dislike]: States.Disliked
            }
        },
        [States.Liked]: {
            on: {
                [Actions.Like]: States.Empty,
                [Actions.Dislike]: States.Disliked
            }
        },
        [States.Disliked]: {
            on: {
                [Actions.Like]: States.Liked,
                [Actions.Dislike]: States.Empty
            }
        }
    }
};

const transition = (action: Actions) => {
    const nextState = state.states[state.currentState].on[action];

    if (nextState) {
        state.currentState = nextState;
    }
};

transition(Actions.Like);
transition(Actions.Like);
transition(Actions.Like);
transition(Actions.Dislike);